1. Field of the Invention
The present invention relates to an apparatus for active monitoring of combustion instability.
2. Background Information
Combustion instability is the term used for the high-amplitude oscillations that appear in the combustion chambers of equipment such as airplane motors, rocket motors, or industrial furnaces or burners. These oscillations are extremely harmful and can diminish the performance of the system, increase the noise produced, and even in certain cases cause the complete destruction of the chamber because of the vibration engendered.
A method for active monitoring of this instability is also known in which a microphone is used to detect the variations in pressure in the chamber. The microphone signal is processed by a microcomputer and sent to compression chambers comprising loudspeakers installed in the air supplying the flame upstream of the combustion chamber.
When the transfer function between the microphone signal and the loudspeaker is selected correctly, the combustion instability can be suppressed.
Although generally satisfactory, this method has the disadvantage of high energy consumption because of the large quantity of air to be excited, and also of being difficult to implement in terms of the monitoring apparatus.